Biometric sensing devices are increasingly used in conjunction with computer or network security applications, financial applications, surveillance applications, and system access control applications. For example, a common approach to fingerprint identification involves capturing a sample fingerprint image and storing the image and/or the unique characteristics of the fingerprint image. The characteristics of the sample fingerprint may be compared to a reference fingerprint image and/or the unique characteristics of the reference fingerprint image to identify or verify the identity of a person.
Typically, the biometric sensing device is connected to an analog processing channel that includes an analog-to-digital converter (ADC). The resolution of an ADC can be defined as the number of discrete digital values the ADC can produce over the range of analog input signals. For example, an ADC with a resolution of 8 bits can convert an analog input signal into one of 256 digital values. Typically, the biometric image is processed further after being output from the analog processing channel. In some embodiments, the resolution of the ADC can limit the quality or effectiveness of subsequent processing operations because information can be lost or restricted when the analog biometric signals are converted into a relatively small number of discrete digital values.